Morphology optimization in ternary organic solar cells

Ternary organic solar cells have drawn great attention because the highest power conversion efficiencies have reached ~12%, showing a promising prospect for the future applications. However, most reported ternary solar cells focus on the increase of light absorption and the optimization of energy alignment, but ignore the importance of morphology. Herein, we summarize the morphology optimization on the ternary blends with different structural aspects, such as controlling crystallinity, crystal orientation, domain size, and domain purity. Furthermore, the fundamental mechanism of ternary solar cells which is related to the morphology has been described. The efforts here will provide a guiding role for the morphology optimization on the ternary solar cells in the future.